This invention relates to dedicated devices, such as automated data collection readers, having a processor that executes a set of instructions, and more particularly to storing instructions for the processor.
A variety of methods exist for tracking and providing information about items. For example, inventory items typically carry printed labels providing information such as serial numbers, price, weight, and size. Some labels include data carriers in the form of machine-readable symbols that can be selected from a variety of machine-readable symbologies, such as bar code or area code symbologies. The amount of information that the symbols can contain is limited by the space constraints of the label. Updating the information in these machine-readable symbols typically requires the printing of a new label to replace the old.
Data carriers such as memory devices provide an alternative method for tracking and providing information about items. Memory devices permit the linking of large amounts of data with an object or item. Memory devices typically include a memory and logic in the form of an integrated circuit (xe2x80x9cICxe2x80x9d) and means for transmitting data to and/or from the device. For example, an RFID tag typically includes a memory for storing data, an antenna, an RF transmitter, and/or an RF receiver to transmit data, and logic for controlling the various components of the memory device. The basic structure and operation of RFID tags can be found in, for example, U.S. Pat. No. 4,739,328 to Koelle et al. and U.S. Pat. No. 5,030,807 to Landt et al. RFID tags are generally formed on a substrate and can include, for example, analog RF circuits and digital logic and memory circuits. The RFID tags can also include a number of discrete components, such as capacitors, transistors, and diodes. The RF transmission of data can be accomplished with modulated back scatter as well as modulation of an active RF transmitter.
RFID tags can be either passive or active devices. Active devices are self-powered, by a battery for example. Passive devices do not contain a discrete power source, but derive their energy from an RF signal used to interrogate the RFID tag. Passive RFID tags usually include an analog circuit that detects and decodes the interrogating RF signal and that provides power from the RF field to a digital circuit in the tag. The digital circuit generally executes all of the data functions of the RFID tag, such as retrieving stored data from memory and causing the analog circuit to modulate to the RF signal to transmit the retrieved data. In addition to retrieving and transmitting data previously stored in the memory, the RFID tag can permit new or additional information to be stored in the RFID tag""s memory, or can permit the RFID tag to manipulate data or perform some additional functions.
Another form of memory device is an optical tag. Optical tags are similar in many respects to RFID tags, but rely on an optical signal to transmit data to and/or from the tag. Additionally, touch memory devices are available as data carriers, for example touch memory devices from Dallas Semiconductor of Dallas, Tex. Touch memory devices are also similar to RF tags, but require physical contact with a probe to store and retrieve data.
Reader devices for these memory devices employ a processor executing instructions contained in embedded code or in read only memory (xe2x80x9cROMxe2x80x9d), and random access memory (xe2x80x9cRAMxe2x80x9d) for storage of temporary data. Traditionally, these reader devices store much of their instruction sets in a fixed form in a non-volatile memory, such as read-only memory (xe2x80x9cROMxe2x80x9d). More recently, reader devices have taken advantage of reprogrammable non-volatile memories, such as erasable programmable memory (xe2x80x9cEPROMxe2x80x9d), electronically erasable PROM (xe2x80x9cEEPROMxe2x80x9d), and flash RAM to store instruction sets. Programmable memories allow the dedicated device to be reprogrammed without the expense and inconvenience of replacing a ROM or motherboard.
Such approaches have a number of distinct drawbacks, For instance, storing the executable code for anything but the most simple reader device requires a significant amount of non-volatile memory, which can be expensive. The reader device may not be upgradable or may be difficult to upgrade, requiring the entire instruction set to be reprogrammed. Such an upgrade may take a considerable period of time, and may require an expensive service call or return to the manufacturer. Reprogramming the reader device may lead to corrupted executable code, which can render the device permanently inoperative. This is particularly a problem when the size of the program is considerable.
Additionally, the user of a reader device my not be aware of a significant upgrade and may be running old, incompatible or corrupted instruction sets. Furthermore, if the reader device is to be field programmable, then the device will require expensive ports for accepting new instruction sets, such as a PCMCIA card port. Alternatively or additionally, to permit the reader device to be field programmable or configurable to perform a variety of tasks, the device must include numerous switches and a display to permit such field programmability and user feedback to properly and partially or completely reprogram the device in the field, and not require it to be sent back to the manufacturer. Furthermore, by permitting manual reprogramming or reconfiguration of a reader makes the reader susceptible to human error during such manual reprogramming/reconfiguring.
The present invention overcomes the limitations of the prior art and provides additional benefits. Under one aspect of the invention, a RFID tag or other data collection or memory device stores data to control the operation and configuration of a RFID reader or other reading/interrogating device. Aspects of the invention provide a simple, inexpensive and fool-proof reader with controllable functions, where such reader is programmable using a simple interface, and which prevents undesired operation due to intentional or unintentional input or control by a user. One aspect of the invention provides desired capability for the reader without using expensive keyboards or display screens, and permits management to simply, inexpensively and in a tamperproof manner program a reader to perform desired actions or functionality. Possible human error due to manual reprogramming is avoided and inexpensive readers may be produced under aspects of the invention.
In a broad sense, the invention includes an apparatus having a data carrier receiver unit, a memory and a processor. The data carrier receiver unit receives data stored in data carriers such as RFID tags. The memory stores basic instructions for operating the apparatus and has an instruction memory section with several instruction sets stored therein. The processor is coupled to the memory and the data carrier receiver unit. The processor is programmed to read data from a control data carrier and select at least one of the instruction sets in the instruction memory section based on the read data. Thereafter, the processor performs the selected instructions from the instruction set.
The invention also includes apparatus and methods for programming RFID tags, including writing commands to a command RFID tag. The invention includes a download-type apparatus having a communication terminal, a memory and a processor, where the communication terminal is configured to establish a communication channel with an RFID reader. The processor is programmed to write at least one instruction set to an RFID reader, where the RFID reader thereafter reads a command data character to select and execute at least one instruction set.
Additionally, the invention includes a data carrier tag, such as an RFID tag, which includes a memory having a command in a specified field that commands an RFID reader, reading the specified field, to select one of several instruction sets stored in the reader. Indeed, the invention includes any automatically-readable medium to be automatically read by a microprocessor controlled device where the medium stores a data structure. The data structure includes a type field, an instruction set indicator field, and for each indicator field, an instruction set. Each instruction set provides several instructions for controlling operations of an RFID reader device.
Moreover, aspects of the invention include a method of controlling an RFID reader using a control RFID tag, and an automatically-readable medium storing such a method. Furthermore, the invention includes a method of reading RFID tags using a reader. The method includes first reading an instruction set identifier in a control tag. Then, one of several instruction sets stored in the RFID reader are selected based on the instruction set identifier. Thereafter, several RFID tags are read and the selected instruction set is executed until another instruction set identifier in another control tag is read. Further details on all aspects of the invention are found in the claims below.